Conditions of aging include increased inflammation and increased risk for cardiovascular disease, diabetes and several other diseases linked to inflammation such as arthritis, osteoporosis and Alzheimer's disease. Factors that protect against development of these diseases, including exercise, diet and adequate sleep may also be more difficult to control over the course of the aging process. Evidence is mounting, which suggests that cardiovascular fitness, healthy diet and adequate sleep bring high returns in the prevention of inflammation. Sleep duration decreases with aging and two thirds of the population over 65 years of age claim to experience sleep problems at least once a week. At night during healthy sleep, endothelial markers decrease in circulation and blood pressure drops to its diurnal low. Controlled experimental studies of cumulative partial and acute total sleep deprivation have shown that inflammatory systems are activated during sleep loss and that white blood cells (WBCs), interleukin-6 (IL-6) and C-reactive protein (CRP) increase. The mechanism(s) for this activation of the inflammatory system during sleep loss are not known, but we hypothesize that metabolic and autonomic system changes related to aging are involved. We will test this by challenging these systems with a 64 hour vigil, comparing the responses in these systems to normal sleep contrast control conditions, and we will investigate differences between young and elderly, adipose and lean individuals. An additional metabolic challenge includes the fasting oral glucose test conducted at baseline and during the latter part of the vigil.